The question, though, is does it? That's an assumption, really. If 99% of the new players get sucked into the D&D ecosystem they're going to have to make active effort to get out of it. As often pointed out, with VTT play that's more practical than it once was, but that's probably still going to only be a thing for a tiny fraction that wasn't already playing that way.
Essentially, I'm not sure the impact is at all visible, once you spread it around among multiple other games, some still in the D&D sphere (PF2e, 13th Age, the OS sphere).
As you say here. If you increase the non-D&D player pool by 5%, who's going to actually notice?
Its not even an issue of being beneficial to an individual; its a question of whether, in practice, its visible to anybody.